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NNTP-Posting-Date: Sat, 08 Aug 2026 05:35:37 +0000
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From: steve g <Sgonedes1977@gmail.com>
Newsgroups: comp.lang.c++,comp.lang.c
Subject: Re: Tic Tac Toe Quest
References: <114cqjo$rh2p$2@raubtier-asyl.eternal-september.org> <114cqrq$rjmv$1@dont-email.me> <114crl1$rt8j$1@raubtier-asyl.eternal-september.org> <114hep7$203s$1@nnrp.usenet.blueworldhosting.com> <114i3ui$2mvma$1@raubtier-asyl.eternal-september.org> <114j66g$256i$1@nnrp.usenet.blueworldhosting.com>
Date: Sat, 08 Aug 2026 01:35:27 -0400
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Xref: csiph.com comp.lang.c++:124606 comp.lang.c:400927

R Kym Horsell <kym@sdf.org> writes:

> OK. It took a while to get an 8" floppy drive working to find
> the code but this is the way we did it in 1979:
>
> Reading it again it's very much in the line of what the kids these
> days call a "prompt".
>
> main :- assert(games(0)), assert(draws(0)),
> 	play(Winner,Moves,FinalBoard),
> 	inc_games,
> 	(Winner=draw -> inc_draws),
> 	fail	%%% force it to try all possibilities (above) trying to succeed
>
> ;	games(Games),writeln(Games),
> 	draws(Draws),writeln(Draws)
> .
>
> %% x goes first
> %% 1222560
> %% 362880
>
> play(Winner,G,B) :-
> 	empboard(B), InitEmp=[1,2,3,4,5,6,7,8,9],
> 	%% player(First),
> 	First=x,
> 	game(First,B,G,InitEmp,FinalEmp),
> 	(	player(Winner),won(Winner,B)
> 	;	Winner=draw, FinalEmp=[]
> 	)
> .
>
> game(_,_,[]) --> [].	%% return short solutions first
> game(Me,B,[M|Ms]) --> select(M),
> 			{ updboard(Me,B,M), opponent(Me,You) },
> 			game(You,B,Ms).
>
> updboard(Who,B,M) :- arg(M,B,Sq), empty(Sq), Sq=Who.
>
> won(Who,B) :- hasrow(Who,B)
> ;		hascol(Who,B)
> ;		hasdiag(Who,B)
> .
>
> %% 1 2 3
> %% 4 5 6
> %% 7 8 9
>
> hasrow(Who,B) :- checksqs([1,2,3],Who,B)
> ;		checksqs([4,5,6],Who,B)
> ;		checksqs([7,8,9],Who,B)
> .
>
> hascol(Who,B) :- checksqs([1,4,7],Who,B)
> ;		checksqs([2,5,8],Who,B)
> ;		checksqs([3,6,9],Who,B)
> .
>
> hasdiag(Who,B) :- checksqs([1,5,9],Who,B)
> ;		checksqs([3,5,7],Who,B)
> .
>
> checksqs([],_,_).
> checksqs([I|Is],Who,B) :- arg(I,B,Sq), Sq == Who, checksqs(Is,Who,B).
>
> empboard(B) :- functor(B,board,9).
>
> empty(Sq) :- var(Sq).
>
> player(Who) :- opponent(Who,_).
>
> opponent(x,0).
> opponent(0,x).
>
> inc_games :- retract(games(X)),X1 is X+1,assert(games(X1)).
>
> inc_draws :- retract(draws(X)),X1 is X+1,assert(draws(X1)).


some beautiful code. I wish I still had my cassette tapes..